The present invention relates generally to a spiral-flow barrel finishing machine comprising a cylindrical stationary metallic barrel equipped with a lining layer at a lower inside part and a rotating barrel which is equipped with a lining layer on a metallic rotational body and loosely engaged with the lower part inside of the cylindrical stationary barrel so s to rotate freely. More particularly, the present invention relates to such a machine including a gap adjusting function that provides an escape layer (such as an air layer) between the inner side of the metallic wall of the stationary barrel and the outer side of the lining layer provided on the metallic wall to allow for the lining layer to thermally expand outwardly and keep the rotary barrel spaced away from the stationary barrel opposite it, regardless of whether the lining layer expands or not. The present invention also includes a method of providing the escape layer and a method of adjusting the gap between the stationary barrel and the rotary barrel.
As shown in FIG. 11, when workpieces are processed by a spiral-flow barrel finishing machine 15 which is running continuously for a long time, the temperature within stationary and rotary barrels 4, 12 is rising, or water is absorbed by respective lining layers 3, 14 on the stationary and rotary barrels 4, 12. In either case, the lining layer 14 on the rotary barrel 12 may expand outwardly, and the lining layer 3 on the stationary barrel 4 may expand inwardly. When this happens, the gap S between the two barrels 4 and 12 will be almost or completely lost, which may eventually make the rotary barrel 12 non-rotational.
An attempt to identify what causes such problems was made, and it has been found that when the lining layer 3 on the stationary barrel 4 should be expanding toward the metallic wall 1 of the stationary barrel 4, the expansion will be prevented by the metallic wall 1, and will instead go toward the center of the stationary barrel 4 (that is, in the direction of narrowing the gap between the stationary barrel 4 and the rotary barrel 12).
The inventors of the current application proposed to provide a stationary barrel 4 in their prior invention (as filed under U.S. patent application No. 08/806,623 corresponding to EP 0791430 A1) that includes a continuously foamed neoprene rubber plate 2 first mounted on the inner side of the metallic wall 1 and a polyurethane lining layer 3 then formed thereon (FIG. 9), thereby allowing the lining layer 3 to expand flexibly outwardly.
In the above invention, a stationary barrel 4 including an air layer 5 in place of the neoprene rubber plate 2 was also proposed (FIG. 10).
Although good results were actually provided by the before mentioned stationary barrel 4 including the neoprene rubber plate 2, it was discovered that the neoprene rubber plate 2 must be thicker, e.g., about 6 mm thick, in order to reduce the resistance against the deformation of lining layer 3 when the lining layer 3 expands flexibly. It was also found that as the neoprene rubber plate 2 becomes thicker, the lining layer 3 must be the thinner.
For the before mentioned stationary barrel 4 including the air layer 5, there is no problem with the thickness that occurs for the neoprene rubber plate 2, but a mold must be provided for forming the air layer 5, and non-compressed fluid such as water must go in and out so that the mold material can be prevented from deforming at the time of liquid injection of the lining. This increases the overall cost.
In light of the above problems, and to solve them, the present invention provides a spiralflow barrel machine having a stationary barrel and a rotary barrel, wherein means is provided for detaching the lining layer, the detaching means extending over specific upper and lower areas of the metallic wall of the stationary barrel corresponding to the position of the small gap between the stationary and rotary barrels, and a small air layer (escape layer) is provided between the inner surface of the metallic wall of the stationary barrel and the outer surface of the lining layer formed on the metallic wall of the stationary barrel in the usual manner after the before described detaching means is provided. The small gap clearance between the stationary and rotary barrels may be adjusted by communicating the small air layer (escape layer) to the atmosphere for allowing the lining layer to be flexible. Alternatively, the small gap clearance may be adjusted by varying the internal pressure within the small air layer (escape layer). To make the formation of the air layer (escape layer) easier, it may be provided so as to extend from the middle portion of the stationary barrel to its bottom end.
One object of the present invention is therefore to provide a spiral-flow barrel finishing machine having a cylindrical stationary barrel and a rotary barrel closed at the bottom thereof, wherein it includes a gap adjusting function in the form of an escape layer extending over a specific area between the inner side of the metallic wall of the stationary barrel and the outer side of the lining layer formed thereon.
Another object of the present invention is to provide a spiral-flow barrel finishing machine having a cylindrical stationary barrel and a rotary barrel closed at the bottom thereof, wherein it includes a gap adjusting function in the form of an escape layer formed between the inner side of the metallic wall of the stationary barrel corresponding to the position of the gap between the stationary barrel and the rotary barrel opposite it and the outer wall of a lining layer formed on the metallic wall of the stationary barrel and extending over the outer bottom surface of the lining layer, allowing for expansion of the lining layer.
The before described escape layer is provided to allow for expansion of the lining layer wherein it is an air layer open at the bottom or a sponge layer.
Alternatively, the another construction may be used wherein the metallic wall includes a projection on its inner side located at the bottom end of the stationary barrel and in the neighborhood of the top of the before described escape layer, the projection extending into the lining layer and being buried therein.
A further object of the present invention is to provide a method of forming an escape layer on a spiral-flow barrel finishing machine having a cylindrical stationary barrel and a rotary barrel wherein it includes providing means for detaching a lining layer to be formed on the metallic wall of the stationary barrel. The detaching means is provided on the inner side of the metallic wall of the stationary barrel and extends over a specific area from upper and lower portions thereof corresponding to the position of the small gap between the stationary and rotary barrels, forming the above-mentioned lining layer on the inner side of the metallic wall of the stationary barrel, and forming an escape layer at the location where the detaching means was provided.
A mold release may be used as the before described detaching means, so that the escape layer is formed by contraction when the lining formed is allowed to harden.
Still another object of the present invention is to provide an escape layer in the form of an air layer that communicates to the atmosphere.
A further object of the present invention is to provide a method of forming an escape layer on a spiral-flow barrel finishing machine having a cylindrical stationary barrel and a rotary barrel closed at the bottom thereof, including providing means for detaching a lining layer to be formed on the metallic wall of the stationary barrel and including a mold release. The mold release extends over a specific area between the middle portion of the inner side of the metallic wall of the stationary barrel and the bottom end of the stationary barrel, and forms the above-mentioned lining layer in the usual manner. A further object of the present invention is to provide a method of forming an escape layer on a spiral-flow barrel finishing machine wherein it includes providing an escape layer molding means at the bottom end on the inner side of the metallic wall of stationary barrel, and forming a lining layer in the usual manner.
Another object of the present invention is to provide a method of adjusting a gap between a stationary barrel and a rotary barrel on a spiral-flow barrel finishing machine, wherein it includes adjusting the internal pressure in the before described escape layer between the inner side of the metallic wall of the stationary barrel and the outer side of the lining layer formed thereon, thereby adjusting the gap.
As described, the detaching means may include a mold release, specifically silicone resin or fluororesin, that may be sprayed or blown. It is noted, however, that any mold release that is known may also be used. The important consideration is that when a lining material, such as polyurethane, is surface processed, it should be easily detached from the metallic wall of the stationary barrel without permanently adhering to the metallic wall, or may be easily detached when it becomes hard by contraction. It should be noted that the part of the lining layer not facing the escape layer should remain attached tightly to the metallic wall. It is therefore preferable that the metallic wall is pre-processed (such as to present a rough surface or to include a binder).
The present invention includes a spiral-flow finishing barrel finishing machine that includes an escape layer (air layer) extending over a specific area between the inner side of the metallic wall of the stationary barrel and the outer side of the lining layer formed thereon. The present invention also includes a spiral-flow barrel finishing machine having a cylindrical stationary barrel and a rotary barrel wherein means for detaching a lining layer to be formed on the metallic wall of the stationary barrel is provided on the inner side of the metallic wall of the stationary barrel facing the small gap between the stationary and rotary barrels and extending over a specific area between upper and lower portions. The above-mentioned lining layer is formed, and an escape layer is provided between the inner side of the metallic wall and the outer side of the lining layer at the location where the detaching means was provided contraction when the lining layer becomes hard. In addition, the present invention includes a method of forming an escape layer (air layer) on the stationary barrel, and also includes a method of adjusting the small gap between the stationary and rotary barrels by adjusting the internal pressure in the escape layer.
The escape layer (air layer) may be provided, starting with the bottom end of the stationary barrel and extending to a specific height.
The machine can be running without any problem if the small gap S between the stationary and rotary barrels is set to the minimum value as long as it does not affect the rotation of the rotary barrel, and the small gap S may be adjusted by adjusting the internal pressure of the escape layer (air layer).
The method according to the present invention allows the air layer to be formed simply by applying a coating of mold release onto the particular part of the stationary barrel and then by taking advantage of the volume contraction when the lining material hardens. Thus, the air layer may be obtained more economically, precisely and automatically than with the conventional method.
The air layer that is provided internally allows for the outward thermal expansion of the lining layer 3. The air layer may be about 1 mm in width, which may still provide the performance reliably. Thus, the lining layer 3 may be thicker. The result is to make the life of the barrels longer.